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But I also have a upper and lower hole to mount on the front spring box so how many IC adjustments is that now....

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According to me, 4! According to Caltracs & Leaf suspension haters, 0.

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OK - now I am going to have to do some research. But first here is what I "think".

It has been my understanding the IC is the EFFECTIVE lifting point of the suspension system not the mounting point of the suspension. This effective point is determined by the force vectors created by the mounting points. A 4-link IC is not at its mounting point but at an imaginary intersection point of the force vectors created by the bars.

So wouldn't the cal-trac bar be transferring an "effective" lift point different from the spring mount? Thereby changing the IC? It is at a different angle than the spring. With the spring wrap the shortening the front segment, it is effectively the top bar of a four link, and the leverage of the Caltrac bar being mounted lower than the axle, getting pushed forward, it would effectively be the lower bar of a four link. Changing the relationship between the two should move the effective IC. And moving the cal-trac bar up or down will change the forward force point, which would mean the IC would change.

My curiosity is peaked on this one, so I will go hit up a couple of PE's for answers.

Also, just because a system has more adjustment points (more IC's) doesn't make it "better" Only a few of the IC points are even close to correct on any given car even with a four link.

Don't get me wrong, I fully believe a leaf spring system is much less than ideal, but it can be made to work fairly well on many cars. Just for reference my last "street" car was a ladder bar setup and my new one is a true four link.

And looking back at an earlier post, I don't see the RMS Street Lynx having less strength than the Unlawful unit. Both have solid top and bottom bars, both mount the lowers at the original spring perch and the top bars to a bar welded between the frame rails. Both bolt to the housing using U-bolts. The RMS has three U-bolts per side, and I only see two in the posted Unlawful picture. Both allow for larger tires than leaf springs.

I do like the RMS Lynx having the shocks mount in front of the rear end housing, making it fit much more easily in a A-body even with the spare tire well.

So I guess it boils down to prices vs performance goals/gains.

Cal-Tracs w/ mono springs and rancho shocks - $815
RMS lynx - all parts included w/QA1 shocks $1795
Unlawful w/all parts included $3995
4-link $4,000 to - $9,000 depending on who, and what is done.

Scott

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Or you could make your own triangulated 4-link set up for around $1000.00

Scott

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other than preload, its not adjustable.

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Again, not true. You can select one of the two holes to change the IC which affects how hard your tires hit, among other things.

And I noticed you edited your post. You had originally said:

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Cal-Tracs will make your car squat, which is wasted motion and time not going forward.

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Definitely not true. My car does not squat when I launch with my Caltracs.

Now before you get all agitated, let me point out that you are affiliated with UnlawfulRacing and you're biased towards favoring your own products. That is perfectly understandable and just fine. Nothing wrong with that.

And then you've also got to realize that people have to take everything you say with a grain of salt because of that.

Now, an important thing to keep in mind when trying to sell your product, is to not bash anybody else's product. This is because when you say something that someone refutes, you just end up with your foot in your mouth and that is not going to help sales.

Just trying to be helpful and give you constructive criticism. Going back to my corner now.

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OK - now I am going to have to do some research. But first here is what I "think".

It has been my understanding the IC is the EFFECTIVE lifting point of the suspension system not the mounting point of the suspension. This effective point is determined by the force vectors created by the mounting points. A 4-link IC is not at its mounting point but at an imaginary intersection point of the force vectors created by the bars.

So wouldn't the cal-trac bar be transferring an "effective" lift point different from the spring mount? Thereby changing the IC? It is at a different angle than the spring. With the spring wrap the shortening the front segment, it is effectively the top bar of a four link, and the leverage of the Caltrac bar being mounted lower than the axle, getting pushed forward, it would effectively be the lower bar of a four link. Changing the relationship between the two should move the effective IC. And moving the cal-trac bar up or down will change the forward force point, which would mean the IC would change.

My curiosity is peaked on this one, so I will go hit up a couple of PE's for answers.

Also, just because a system has more adjustment points (more IC's) doesn't make it "better" Only a few of the IC points are even close to correct on any given car even with a four link.

Don't get me wrong, I fully believe a leaf spring system is much less than ideal, but it can be made to work fairly well on many cars. Just for reference my last "street" car was a ladder bar setup and my new one is a true four link.

And looking back at an earlier post, I don't see the RMS Street Lynx having less strength than the Unlawful unit. Both have solid top and bottom bars, both mount the lowers at the original spring perch and the top bars to a bar welded between the frame rails. Both bolt to the housing using U-bolts. The RMS has three U-bolts per side, and I only see two in the posted Unlawful picture. Both allow for larger tires than leaf springs.

I do like the RMS Lynx having the shocks mount in front of the rear end housing, making it fit much more easily in a A-body even with the spare tire well.

So I guess it boils down to prices vs performance goals/gains.

Cal-Tracs w/ mono springs and rancho shocks - $815
RMS lynx - all parts included w/QA1 shocks $1795
Unlawful w/all parts included $3995
4-link $4,000 to - $9,000 depending on who, and what is done.

Scott

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Or you could make your own triangulated 4-link set up for around $1000.00

Scott

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With my fabricating and welding skills that would end up looking like cobbled up piece of crap lol
So for me that's not a option I got a good deal on a "bandaid" Caltrac system so I hope I didn't waist my hard earned money.

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Scot, I have never had a 60' better than 1.54.
I was 1.60 before but I always had tire spin off the line. Now I am limited by horespower.

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Nice car . Is it still spinning off the line? Was the 1.54 spinning with the new rear suspension?

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Suspension 101...

The IC (Instant Center) of any suspension system, is the point where the forces from the rearend housing, apply themselves to the chassis. Basically, a ladder bar, is like a leaf spring, but the advantage is the ladder bar will not give, plus it moves the IC forward because of bar length. This applies force to the chassis further forward, creating better leverage and increased weight transfer. If you could make your front spring segment dead stiff and move the mounting point out even with the ladder bar, it would be as good as a ladder bar. All this is why link suspensions, be it a 3 or 4 link, is far superior. You can place the IC where it NEEDS to be, to properly apply the force to the chassis, to get the results you desire........Oh, one more thing, if you followed this at all and learned anything about how suspensions work, you can also see why good SHOCKS are critical for a good working car. The whole exercise is about "controlling the housing and applying force". You can have the trickest suspension in the world, but junk shocks render it useless.

Monte

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If I had talked to someone like Monte before I purchsed my Caltracs and split mono leafs, I would of bought Chevy length springs which are 5 inches longer in the front segment of the spring. This would of required a little more fabrication, but I think in my case of trying to hook up a 10.5 tire with a BB nitrous trans brake combo, it would of helped. Next step is "good" shocks, and maybe a glide($). I have to run the leafs to be legal in my heads up class, but that triangulated 4 link looks like a nice system. I hope the original poster got some helpful info from his question? I know I'm getting something out of it.

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Suspension 101...

.......Every car has an "anti squat line". This line extends from the center of gravity, down to the front of the contact patch of the rear tire. If the suspension pickup point, is below the anti-squat line, the car seperates in the rear on launch. If the pickup point is above the anti-squat line, the car squats on launch. If the the pickup point is on the line, the car does neither. Some suspension guys, theorize the IC ON the anti-squat is ideal for any application, because this is where the car has the least wasted movement and applies the most power, but my own testing does not seem to support that...........Basically, a ladder bar, is like a leaf spring, but the advantage is the ladder bar will not give, plus it moves the IC forward because of bar length. This applies force to the chassis further forward, creating better leverage and increased weight transfer.

If you could make your front spring segment dead stiff and move the mounting point out even with the ladder bar, it would be as good as a ladder bar. All this is why link suspensions, be it a 3 or 4 link, is far superior. You can place the IC where it NEEDS to be, (which, may be RIGHT ON the anti-squat line??? )to properly apply the force to the chassis, to get the results you desire........

Oh, one more thing, if you followed this at all and learned anything about how suspensions work, you can also see why good SHOCKS are critical for a good working car. The whole exercise is about "controlling the housing and applying force". You can have the trickest suspension in the world, but junk shocks render it useless.

Monte

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Yeah, shocks are to keep the car from seperating or squatting IF the IC isn't on the anti-squat line?????......... .......just food for thought.......

Hey Monte, in your spare time, it'd be very interesting to test a 4 link car like this.......Put the IC on the anti-squat line, make three passes...........then take OFF the shocks and make three more passes and see what it does.........Those that claim that the IC needs to be on the anti-squat line also say that shocks don't do anything and aren't even needed on the rear because the body of the car is neither seperating or squatting.......(if the track is flat, but that's another story)..........

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plus, how you going to hold the car up.

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Is this a trick question? Shocks don't hold the car up. The springs do. If you remove shocks from a car at rest, the car doesn't fall down.

Wayne has an excellent point - if your IC is exactly on your resultant vector then the rear shocks don't do anything at all. The springs aren't compressing or decompressing.

That is until you hit that nasty pothole in the track and then bazoing-oing-oing-oing-oing-oing...